Dexamethasone Versus Ondansetron for Preventing Post-Spinal Hypotension in Preeclampsia

Intravenous Dexamethasone Versus Ondansetron in the Prevention of Post-Spinal Hypotension in Preeclampsia Patients Undergoing Caesarean Delivery: A Prospective Randomized Clinical Trial

This study compares the efficacy and safety of intravenous dexamethasone versus intravenous ondansetron in preventing low blood pressure (hypotension) following spinal anesthesia in pregnant women with preeclampsia undergoing scheduled cesarean delivery.

Spinal anesthesia is the preferred anesthetic method for cesarean delivery, but it frequently causes a sudden drop in maternal blood pressure. In patients with preeclampsia, post-spinal hypotension can compromise blood flow to the placenta and vital organs. While traditional vasopressor medications are used to restore blood pressure, non-adrenergic prophylactic agents such as dexamethasone and ondansetron may help maintain hemodynamic stability through different physiological pathways.

Participants will be randomly assigned to receive either intravenous dexamethasone (8 mg) or intravenous ondansetron (4 mg) 15 minutes prior to the initiation of spinal anesthesia. Blood pressure, heart rate, vasopressor requirements, optic nerve sheath diameter, and maternal and neonatal outcomes will be monitored throughout the surgery and during the immediate postoperative period.

Inclusion Criteria:

• Pregnant women aged 18 to 40 years.
• American Society of Anesthesiologists (ASA) physical status III.
• Diagnosed with preeclampsia (new onset of hypertension ≥140/90 mmHg with proteinuria occurring after 20 weeks of gestation according to ACOG and ISSHP guidelines).
• Scheduled for elective cesarean delivery under spinal anesthesia.

Exclusion Criteria:

• Peripartum bleeding.
• Obesity (body mass index ≥40 kg/m²).
• Coagulation disorders (platelet count < 75,000/μL).
• Neurological disorders.
• Previous or current systemic corticosteroid therapy.
• Known cardiac disease.
• History of diabetes mellitus.
• Renal dysfunction (serum creatinine > 2 mg/dL).
• Hepatic dysfunction (serum liver enzymes > 2 times the upper limit of normal).
• Known hypersensitivity to dexamethasone, ondansetron, or any component of the study medications.
• Emergency cesarean delivery.
• Known fetal congenital anomalies.